Vapor electric apparatus.



J. T. H. DEMBSTER.

VAPOR ELEGTilIC APPARATUS.

APPLICATION FILED JAN. 14, 1908.

Patented Mar. 29, 1910.

Inventor John T. H. Dpster,

Witnesses:

NITED STATES rATENroFmoE.

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nnncrmc I ii EIniT NEW Yon-x, nssmno so ,1. COMPANY; A .GQRPORATION 0F$03K.

VAPOR ELECTRIC APPARATUS.

Tovall whom it may 'Beit known that (I, JOHN TI. DEMP- srmn, a citizenofthe United States, residing at Schenectady, county of Schenectady, Stateof New York, have invented certain new and useful improvements in Va orElectric Apparatus, of which the following is a specification.

The object of my invention is to avoid 'the difhculties caused byconductors extending through and sealed into the walls. of vessels ofporcelain, glass and similar materials; to eliminate the strains andleakage caused by the conductors, and to provide a simple and reliablemeans for hermetically sealing refractory vessels afterthey have beenexhausted.

in carrying out my invention, the strains upon the Walls of the vessel,due to the presence of metallic conductors, are eliminated by passingthe current directly through the wall of the .vessel, while if thevessel is made of refractory material it is sealed by fusing into theexhaust opening a plug or stopper composed of some material which makesa hermetical joint with the walls of the opening.

My invention will best be understood in connection with the accompanyingdrawing, which is merely an illustration of one of the many forms inwhich the invention may be embodied, and which shows a vessel orreceptacle lmade in the form of a mercury arc lamp or rectifier.

The vessel is provided onthe sides with tubular projections 2, and onthe bottom with similar projections containing the mercury. Inaccordance with my invention, the

- Wallspf the vessel are not weakened by being plerced for theconductors, but the current is conducted directly through the Walls bymaking the walls at the desired points of some material which is aconductor of the second class and is non-conducting at ordinarytemperatures but becomes more and more conductive as it is heated. Thewalls need be made of a conductor of the second class only at the pointsat which current is passed through them, although ordinarily the entirevessel will be made of the same material. The current may be passedthrough the selected portions of the walls, which in the device shown inthe drawing would be the tips of the tubular projections, by makingthose portions of the walls of porcelain or other conductor of thesecond class and by providing some suitable means for passing thecurrent through them. Porcelain of the composition commonly used inelectrical work for insulators issuitable for this purpose as is alsothe porcelain commonly used for crucibles and test tubes, The preferredv rent through the Wall comprises some suitable means for heating thewall at the desired point until it becomes sufficiently conductive topermit the desired amount of current to flow into the vessel and alsofor insuring that the current will flow through the heated portion.Thisresult may be secured by any suitable means, such as oooperatingconductors on opposite sides of the heated portion, as shown in thedrawing, in which the internal conductor 3 is placed in the end of eachtubular projection 2 in contact with the walls at the desired point, anda corresponding and codperating exter nal electrode 4 mounted on andsurrounding the end of the tubular projection is connected to leads 5 bymeans of which current is supplied to the device. Theelectrodes may bemade of any suitable material, such as iron. That portion gt the tubularprojection between these conductdrs ismade of a conductor of the secondclass and is rendered conductive by heating it to the proper temperatureby any suitable device, such as the electric heater 6 shown in thedrawing, consisting of a shell of non-conducting material lined with aheating coil of platinum or similar material supplied with currentthrough the conductors 7.

The form or" vessel is, of course, immaterial, although that shown inthe drawings is advantageous when the entire vessel is made of aconductor of the second class, since the tubular projections 2, whichcarry .the cooperating electrodes, are easily heated at the point atwhich it is desired to pass the current into the vessel to such atemperature that the Wall of the projection between the electrodesbecomes conductive Without causing the remainder of the vessel to becomeso hot that it loses its insulating properties.

In the operation of the device a small spot between the electrodesbecomes red hot and then the current flowing through the wall at thatspot keeps it hot enough to conduct the current. Where the electrodesmeans for passing the curx L Specification of Letters Patent. Pat t r299 19108 Application med January 14, 190 8. finial Io. 10,168.

are made in the form shown in the drawing i and are secured to the endsof the tubular projections 2, they strengthen the walls of t the tubeand confine the heat to a small spot I at a considerable distance fromthe body of the rectifier. If the entire vessel is made of a refractoryconductor of the second class, such as port celain, difiiculty may beencountered in maki ing the seal after the vessel is exhausted. Inaccordance with my invention, the vessel is provided with an exhaustoutlet 8 by 9 means of which it is connected to the exj haustion pump,and in this outlet is placed I a sealing plug 9 made of any suitable ma-I terial which will fuse at a lower temperature than the walls of theexhaust opening 8-, and which when fused will make a hermetical jointwith the walls of the exhaust 7 opening. The plug or seal may be a metalball, or if the vessel is made of porcelain, the seal is preferably madeof glazed porcelain, with a covering of glaze so thick that when theoutlet 8 is heated the glaze on the seal 9 unites with the walls of theoutlet opening and forms a hermetical joint. My invention may beembodied in many I other forms than that shown and described and I,therefore, do not wish to be restricted l to the exactform shown, butintend to cover by the appended claims all changes and modificationswithin the spirit and scope of my invention.

What I claim as new and desire to secure by I letters Patent of theUnited States, is,-

1. The combination with a vessel having a wall composed of a conductorof the second class, of'cooperating electrodes in engagement withopposite sides of .said wall for conducting current into the vesselthrough said wall when said wall is heated. 2. The combination with avessel having a wall composed of a conductor of the secv i l i I ondclass, of cooperating electrodes on opposite sides of said wall, andmeans for raising the temperature of said wall to render it conducting.

3. The combination vessel having a wall composed of a conductor of thesecond class, of cooperating interior and exterior electrodes inengagement with said wall, and means for heating the I wall between saidelectrodes to render it conductive.

t. In a vapor electric device, the combination with an evacuated vesselhaving a wallcomposed of a conductor of the second class, of an interiorelectrode in engagement with the inner side of said wall and an eX-terior cooperating electrode in engagement with the outer side of saidwall and 1n allnement with said interior electrode whereby current tooperate the device is conducted into the vessel through said wall whensaid wall is heated.

5. In a vapor electric device, the combination with an evacuated vesselhaving a porcelain wall, of coiiperating electrodes in engagement withopposite sides of said wall,

I and a heater for rendering the porcelain l between the electrodesconductive.

6. In a Vapor electric device, the combination with an evacuated vesselhaving tubular projections with the end walls thereof composed 'of aconductor of the second class, of interior electrodes in the ends ofsaid projections, exterior electrodes encir cling the ends of saidprojections, and heaters encircling the ends of said projections torender the end walls conductive.

In witness whereof, I have hereunto set my hand this 13th day ofJanuary, 1908.

. JOHN T. H. DEMPSTER.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

with an evacuated.

